Arterial Stiffness Predicts Myocardial Perfusion Reserve: An Adenosine Stress Cardiac Magnetic Resonance Study

Abstract

Introduction: Increased large artery stiffness is associated with adverse cardiovascular outcomes, related to an increase in cardiac work and reduction in coronary blood flow (CBF). We sort to assess a simple non-invasive method, adenosine stress cardiacMRI (ASCMR), in determining the relationship between large artery stiffness and myocardial perfusion. Methods:We studied 40 subjects with stable chest pain referred for ASCMR who were subsequently found to have no myocardial ischaemia and normal LV function. ASCMR was performed with a standard infusion protocol. Three short-axis images of LV were obtained at stress and rest. Cross-sectional area of the mid thoracic descending aorta was measured and aortic distensibility (AD, inverse of stiffness) calculated as (aortic area in systole− aortic area in diastole)/(pulse pressure× aortic area in diastole). Left ventricular perfusion was evaluated off-line using QMass software. The myocardial perfusion reserve index (MPRI) was calculated as (Myocardial Blood Flow At Stress/Myocardial Blood Flow At Rest) and was represented as an average of all myocardial segments. Results: Forty patients were studied (60± 11 years; 19 males). At baseline mean BP was 107mmHg (range 76–133). On univariate analysis AD correlated with MPRI (p= 0.015, r= 0.433). After accounting for other clinical variables including hypertension, smoking, diabetes, hypercholesterolaemia and gender in multivariate analysis, correlation between AD and MPRI remained (p= 0.031). Age also correlated with AD as demonstrated in earlier studies. Conclusion: ASCMR can demonstrate relationship between arterial stiffness and MPRI. This offers potential to evaluate impact of other disease processes known to increase aortic stiffness on ventriculo-vascular interaction and CBF.